Current-meter.



H. E. POPP.

C U R R E NT M ETE R.

APPLICATION FILEVD AFR.5.1915.

Patented Deo. 19, 1916.

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v CURRENT-METER.

Specicaton of Letters Patent. Patnted Dec, 19, 1916,

Application filed April 5, 1915. Serial No. 19,153.

To all whom it may concern:

Be it known that I, HARRY E, Pori?, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Current-Meters of which the following is a specification.

My invention relates to improvements in current meters, and the improvements comprise the simple and practical means herein shown and described and more particularly pointed out in the claims, whereby the ow of water in large pip, open channels or rivers, may be gaged and measured' with accuracy and despatch.

In the accompanying drawings, Figure. l is a sectional view longitudinally through the central axis of the device, and Fig. 2 is a transverse section'on line 2-2, Fig. 1. Fig. 3 is a longitudinal section on line 3-3,

the front parts being omittedf One accepted way of gaging the flow of water'in large pipes, open channels or rivers, is by means of a current meter comprising a series of vanes or cups mounted on the periphery of a wheel which is immersed in the stream to cause the wheel to revolve. At every certain number of revolutions of the wheel an electrical contact is made to produce an audible signal to an observer who is thereby enabled to maintain a count of the number of revolutions of the wheel and to estimate the velocity of flow of the water. Although several approximate methods of using this instrument for more rapid determinations of the mean velocity of the stream are in vogue, the most usual and also the most exact method for accurate work known to me consists in placing the meter at many diderent points in the cross section of the stream, allowing it to remain at each point long enough to enable the observer to determine the number of revolutions of the wheel 'per minute and thereby the velocity of the water at that point. Unless these points are so selected that the individual velocities determined, may be taken to represent the velocity over equal portions of the cross section of the stream, which is only possible when the cross section is a regular ligure, the arithmetical means of all thev velocities determined is not the true mean 'velocity of the stream. It is therefore necessary, usually, zontal or vertical lines and knowing their relative positions to plot a graphical chart -graphical chart to select the points in horishowing the distance between points as a base, and the velocities at the points as ordinates, the average ordinate of the curve thus drawn representing the average velocity over the strip of area covered by these velocip- The objection to this method lies in the fact thatk since the'meter must be left at each point for several minutes thetime consumed in making a large number of determinations is very considerable. A further objection is the very great error which yis often introduced by the effect of eddies and cross currents on the speed of the meter.

The purpose of my invention, therefore, is to provide an instrument which will be acted upon very nearly only by the component of the velocity at right angles to the cross section of the channel, and which if a suitable recording mechanism were used but which is not shown herein would produce a showing the velocity of the water at every point in a portion of the cross section of the channel as the meter is raised or lowered vertically therein. A The instrument is based on the well known hydraulic phenomenon that a stream of water or other fluid impinging on a small tube having the plane opposed to the direction of flow will exert in that tube a pressure equal to the sum of the velocity head and the pressure head of the water at that point; also thata small tube with the plane of the entering orifice parallel to the direction of flow will'have exerted in it a pressure equal or proportional only to the pressure head of the water at that point. It Vis evident therefore that by connecting these two tubes or two equivalent openings to separate chambers on opposite sides of a plunger, a force will be exerted on the plunger equal to the difference between the two pressures, which is simply the velocity head. Thus, vthe velocity head plus pressure head minus pressure head equals velocity head. In brief, it is`this principle which Iwutihze to provide a new type of meter comprising a tubular casing having a removable front nozzle section 2, an intermediate cylinder 3 for a reciprocable plunger 4, and a rear section which is divided longitudinally into two parts, 5 and 6, respectively, to provide a housing for suitable electrical resistance mechanism adapted to be operated by plunger 4. Nozzle section 2 is more or less pointed and has a relatively small intake mouth of the entering orifice 7 axially thereof at its front end, and a screw-threaded extension 8 at its rear end engages cylinder 3. A. transverse diaphragm 9 closes the rear end of cylinder 3, but the cylinder is otherwise open to the entrance of water by way of a series of orliices 10 in the cylinder wall located in front 'ot diaphragm 9. The plunger rod 11 extends through the central boss portion 12 of dlaphragm 9 and its inner screw-threaded end carries the thrust collar 111 of a coiled spring 15 which bears at its opposite end againstva seat l6\at the front end edges ot the middle cross walls 17 and 18 of theil two rear housing sections 5 and 6, respectively. lPlunger rod 11 also carries an upright arm 19 having a rearwardly extending rack bar 20 in gear connection with a small gear 21 mounted on a transverse shaft 23 in the upper .portion of the shallow chamber 24 for the spring contact arm 25 and' the curved resistance wire 26 which is seated in thelat side of a curved segmentbar 27 made of porcelain or other suitable insulating material. The opposite ends of resistance wire 26 are secured to binding posts 27 insulated from the casing,l and a rolling contact is established with wire 26` by a roller 28 on the end of arm 25. The shaft 23 for this arm is insulated from the casing by bushings 29 made of suitable insulating material, and a metal bearing 30 and binding nut Stare provided for one end of the shaft centrallyin one ot' said ybushings at the outside of the casing, the said shaft extending through a transversepassage 32 in the casing section 5, see Fig. 2.. An insulated electrical conductor or cable may be attached to binding post 31 and similar conductors to each binding post 27', these conductors passing through the carrying yoke 32 and its rod ,33, which jointly support the instrument atany depth in a stream of water, and are made ,tubular and hollow to provide a conduit for the electrical connections, see dotted lines, Fig. 2.

rlhe rear end of the casing is closed by a separate plate 35, which Awhen screwed in place, also holds the two sections 5 and 6 together, and the front ends of said sections 5 andv 6 have reduced screw-threaded neck portions 36 adapted to make screw engagement with the rear end of cylinder 3. Flanges 37 on sections 5 and 6 aford further means oit' bolting or screwing them together, and a removable top plate 38 covers chamber 24 and aords a guide for rack bar 20, also permitting accessfor dismantling. The separate compartment 24 isolates the resistance wire 26 and oscillatory contact arm 25 from any water taken into the larger surrounding compartment within sections 5 and 6; in fact, the water level would have to rise to the rack bar 20 compressing the entrapped-alrbefore effecting entrance into compartment 2t naoenaa lin operationythe total head of water (v-ezle mouth 7, and the pressure head only .is f

admitted to the rear side of the plunger t through the orifices 10 in the side ot' the meter casing. 'llhe unbalanced torce on the plunger, then, which is proportional to the velocity-head of the water, is resisted'by spring 15 so that a movement ofthe plunger backward or forward takes Yplace as the velocity of the water impinging on the opening in the front of the meter increases or decreases, the amount of movement being proportional to the change in velocity head. llo increase the accuracy of the instrument, several interchangeable springs would be provided, weaker ones for low velocities and stronger ones for the higher ranges. f

rlFhe proportional movement of the plunger to threJ changes in velocity head of the water is recorded on a chart by suitable electrical reproducing and recording mechanism located at the surface of the water and electrically connected to the resistance wire 26 and arm 25; 1n other words, the movement of plunger 4 is transmitted to arm 25 having sliding engagement with wire 26 to produce variable current in the electrical circuit contained in the reproducing and re- L reciprocatetherein and provided with open-l ings in its walls on opposite sidesk of said plunger to subject the plunger tothe velocity head and pressure head of the stream, and electrical means having operating connections with saidxplunger to transmit' kthe variable movements of said plunger when the instrument is immersed.

2. An instrument for the purposes described, comprising a tubular body having a reciproca-ble plunger therein, and chambers on opposite sides of said plunger in open communication with the front end and side exterior of said body, and provided with a sealed chamber at its rear, in combination with an electrical resistance device confined within said rear chamber and actuating connection between said plunger and device.

3.y A current meter, comprising a perfovided with a compartmented section at its rear, in. combination with an electrical device confined Within said compartmented section having a movable contact member and means to operate said member by the movement of said plunger.

4. In a current meter, a cylinder having a side opening and a plunger'within said cylinder, an intake nozzle at the front of said cylinder, a hollow rear section for said cylinder, a plunger shaft extending into said hollow rear section, electrical resistance means having a movable contact arm in operative connection withl said shaft, -and a i spring toforce the plunger toward the front end ofsaid cylinder.

5. In a device substantially as described, a cylinder having orifices in its side and an intake nozzle at its front end, a plunger Within said cylinder, a shaft and` operating spring for said plunger, a compartmented lrear section for said cylinder, an electrical resistance Wire and contact member engaged therewith within sald rear section, and operatmg connections for said member engaged f With the plunger shaft.

6. An' instrument for gaging the flow of f/ces annularly thereof, a` sprin a liquid comprising a cylinder having oriy pressed plunger Within said cylinder, a, etachable front nozzle for the cylinder having a relatively small intake mouth, ya sectional rear extension for the cylinder having a separate compartment on the median line thereof, a resistance Wirev and an oscillatory contact arm therefor mounted in insulated position Within said compartment and geared connections between said arm and plunger.

7. A submersible device for determining the velocity and discharge of a stream, comprisin a perforated cylinder having a contracte intake nozzle at one end, a reciprocable plunger adjacent said nozzle, a spring backing for said plunger, a variable electrical resistance having a shifting contact member coupled to said plunger, electrical connections forsaid resistance, and means to support Said device Within a stream.

In testimony whereof I affix my signature in presence of a Witness.

HARRY E. PoPP.

Witness Gao. E. KnxonER. 

